This research proposal focuses on the study of stress-resistant children identified by: 1) their maintenance of mastery and competence in 2) the presence of sustained life stresses. Four different forms of stress (stressful life events in families, physical handicap, congenital heart defect, and emotional disorder in parents) and two parallel adult cohorts constitute the groups to be studied. A composite score of competence is built around three components derived from the child's background: work effectiveness, peer preference and effectance motivation based on teacher ratings. A wide range of performance measures of intellect and achievement, social cognition, problem solving, sustained attention, cognitive styles and specific personality attributes are detailed in the proposal. For the congenital heart defect group neurological and psychological assessments are emphasized. Extensive (parent and child) interview data play a significant role with all cohorts in the study. A short-term follow-up of the children is projected.